How to do IS NULL and IS NOT NULL with Yii 2 ActiveRecord?

Question

I have a table which has a field `activated_at` timestamp NULL DEFAULT NULL, which means that it can contain a timestamp or it can be null and it\'s

Answer 1

for this expression:

WHERE activated_at IS NULL

try this (it's working):

->andWhere(['is', 'activated_at', new \yii\db\Expression('null')]),